Today, sick house syndrome is becoming a big problem, in which people feel pains in the eyes and throat, and feel dizzy or get sick when they are indoors. This syndrome is considered to be caused by volatile organic compounds released from building materials, furniture and other daily necessities. One of the reasons why this disease is becoming a big problem is because today's buildings are highly airtight, and due to more frequent use of air-conditioners, interior air is less frequently exchanged, so that volatilized organic compounds tend to remain indoors for a prolonged period of time. In order to cope with this problem, the recently revised Building Standard Acts require the provision of ventilating facilities in every building. Many of today's home air-conditioners are also equipped with ventilating functions to promote ventilation in buildings.
But too much ventilation makes it more difficult to maintain the desired temperature by heating or cooling with minimum energy consumption. For this reason, total heat exchangers are gathering much attention, which can exchange air with minimum release of heat or cold air to the outside, thereby reducing energy consumption.
Such total heat exchangers include a rotary total heat exchanger which transfers heat of exhaust air to intake air by the rotation of a moisture-absorbing rotor, and a static total heat exchanger as shown in FIG. 3. Such a static total heat exchanger includes corrugated total heat exchanger elements 3 having gas barrier properties. When outer fresh supply air 1 and inner polluted exhaust air 2 pass through separate paths in the elements 3, sensible heat is transferred from the exhaust air 2 to the supply air 1. Also, since moisture can penetrate through the elements 3, the latent heat possessed by the water contained in the exhaust air 2 is also transferred to the supply air 1. Thus, it is possible to minimize the release of heat or cold to the outside.
For higher efficiency of heat exchange, the total heat exchanger sheets used for the total heat exchanger elements 3 in such a static total heat exchanger is preferably made of a material which allows permeation of not only sensible heat but moisture and thus latent heat. Such sheets include total heat exchanger sheets using e.g. Japanese paper (Washi), fireproof paper made of pulp, glass fiber-mixed paper or inorganic powder-containing paper. But because ordinary paper allows permeation of air too, sheets having a moisture permeable membrane are frequently used. Such sheets include a hybrid moisture permeable membrane described in examples of Patent document 1, which comprises a porous sheet made of polyethylene or polytetrafluoroethylene, and a moisture-permeable water-insoluble hydrophilic polymer membrane formed on one side of the porous sheet.
[Patent document 1] JP Patent 2639303